Carbon Nanotube

In recent days, Polymer is very useful and important material for its unique properties and applications. A Polymer is a large molecule or macromolecule which is composed of several repeating subunits, called monomer. Polymers are classified depending on several parameters like chemical structure, polymeric structure, arrangement of monomer, tacticity etc. It has several applications in the field of industry, science and medical. Several properties of polymers can be tuned by embedding different materials with it. Among them graphene and carbon nanotube are most desirable material. Graphene is the latest discovery belonging to the group of carbon allotropes and a versatile material in nanotechnogy due to its unique electronic, optical and mechanical properties. It is a two dimensional material, a Single layer of graphite. It has several properties such as conductive, flexible, highly strong and transparent. On the other side, carbon nanotube is most valuable material in several applications for its unique electronic, mechanical and optical properties. Like graphene and graphite, it is also a carbon based material. Due to its high surface to volume ratio, even a low content of nanotube in polymer matrix can change the interphase or interface region which changes their properties significantly. The electromagnetism and microwave absorption properties of several material can be modified by incorporation of desired value of carbon nanotube with that material. Dielectric properties of several polymer materials also can be modified by embedding carbon nanotube with it. It is also acted as a filler material for introducing Piezoelectricity in some Polymer material. Here properties of polymer, graphene and carbon nanotube has been discussed in brief. Synthesis and applications of these three materials are also the key focus of this paper.

Deep Inelastic Neutron Scattering provides a means of directly and accurately measuring the momentum distribution of protons in water, which is determined primarily by the protons ground state wavefunction. We find that in water confined on scales of 20A, this wave function responds to the details of the confinement, corresponds to a strongly anharmonic local potential, shows evidence in some cases of coherent delocalization in double wells, and involves changes in zero point kinetic energy of the protons from -40 to +120 meV difference from that of bulk water at room temperature. This behavior appears to be a generic feature of nanoscale confinement. It is exhibited here in 16A inner diameter carbon nanotubes, two different hydrated proton exchange membranes(PEMs), Nafion 1120 and Dow 858, and has been seen earlier in xerogel and 14A diameter carbon nanotubes. The proton conductivity in the PEM samples correlates with the degree of coherent delocalization of the proton.

TiO2 and SnO2 are the well-known sensing materials with a good thermal stability of the former and a high sensitivity of the latter. Carbon nanotubes (CNTs) have also gas sensing ability at room temperature. CNTs-included SnO2/TiO2 material was a new exploration to combine the advantages of three kinds of materials for gas-sensing property. In this work, a uniform SnO2/TiO2 solution was prepared by the sol gel process with the ratio 3:7 in mole. The CNTs with contents in the range of 0.001 0.5 wt% were dispersed in a mixed SnO2/TiO2 matrix by using an immersion-probe ultrasonic. The SnO2 TiO2 and the CNTs-included SnO2 TiO2 thin films were fabricated by the sol gel spin-coating method over Pt-interdigitated electrode for gas-sensor device fabrication and they were heat treated at 500 °C for 30 min. FE-SEM and XRD characterizations indicated that the inclusion of CNTs did not affect the particle size as well as the morphology of the thin film. The sensing properties of all as-fabricated sensors were investigated with different ethanol concentrations and operating temperatures. An interesting sensing characteristic of mixed SnO2/TiO2 sensors was that there was a two-peak shape in the sensitivity versus operating temperature curve. At the region of low operating temperature (below 280 °C), the hybrid sensors show improvement of sensing property. This result gives a prospect of the stable gas sensors with working temperatures below 250 °C.

We investigate the electronic structure of carbon nanotubes functionalized by adsorbates anchored with single C-C covalent bonds. We find that, despite the particular adsorbate, a spin moment with a universal value of 1.0 $\mu_B$ per molecule is induced at low coverage. Therefore, we propose a mechanism of bonding-induced magnetism at the carbon surface. The adsorption of a single molecule creates a dispersionless defect state at the Fermi energy, which is mainly localized in the carbon wall and presents a small contribution from the adsorbate. This universal spin moment is fairly independent of the coverage as long as all the molecules occupy the same graphenic sublattice. The magnetic coupling between adsorbates is also studied and reveals a key dependence on the graphenic sublattice adsorption site.

Power dissipation is expected to increase exponentially to 150-250 W per chip over the next decade. To manage this large heat output, it is necessary to minimize the thermal resistance between the chip and a heat dissipation unit that the device is attached to. It is therefore important to further improve the thermal performance of thermal interface materials (TIMs), which can be achieved through 1) improvement of the bulk thermal conductivity of TIMs; and/or 2) reduction of interfacial thermal resistances between the TIM and the device and/or TIM and the heat dissipation unit. The latter improvement may be obtained by enhanced physical properties of TIMs (e.g., viscosity or wetting ability) and/or surface modification of the heat dissipation unit or the inactive side of the device. Researchers have tried to take advantage of the high 1D thermal conductivities of graphite fibers, and more recently of carbon nanotubes (CNT), to reduce the thermal resistance between the chip and the h...

A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with carbon nanotubes (CNTs) and catechol compounds. First, 25 μL of DMSO–CNTs solutions (0.4 mg/mL) was cast on the surface of GC electrode and dried in air to form a CNTs film. Then the GC/CNTs modified electrode immersed into a chlorogenic acid, catechine hydrate and caffeic acid solution (electroless deposition) for a short period of time (2–80 s). The cyclic voltammogram of the modified electrode in aqueous solution shows a pair of well-defined, stable and nearly reversible redox couple (quinone/hydroquinone) with surface confined characteristics. The combination of unique electronic and electrocatalytic properties of CNTs and catechol compounds results in a remarkable synergistic augmentation on the response. The electrochemical reversibility and stability of modified electrode prepared with incorporation of catechol compound into CNTs film was evaluated and compared with usual methods for attachment of catechols to electrode surfaces. The transfer coefficient (α), heterogeneous electron transfer rate constants (ks) and surface concentrations (Γ) for GC/CNTs/catechol compound modified electrodes were calculated through the cyclic voltammetry technique. The modified electrodes showed excellent catalytic activity, fast response time and high sensitivity toward oxidation of hydrazine in phosphate buffer solutions at pH range 4–8. The modified electrode retains its initial response for at least 2 months if stored in dry ambient condition. The properties of modified electrodes as an amperometric sensor for micromolar or lower concentration detection of hydrazine have been characterized.

The identification of nanomaterials with the properties required for energy-efficient electronic systems is usually a tedious human task. A workflow to rapidly localize and characterize nanomaterials at the various stages of their integration into large-scale fabrication processes is essential for quality control and, ultimately, their industrial adoption. In this work, we develop a high-throughput approach to rapidly identify suspended carbon nanotubes (CNTs) by using high-speed Raman imaging and deep learning analysis. Even for Raman spectra with extremely low signal-to-noise ratios (SNRs) of 0.9, we achieve a classification accuracy that exceeds 90%, while it reaches 98% for an SNR of 2.2. By applying a threshold on the output of the softmax layer of an optimized convolutional neural network (CNN), we further increase the accuracy of the classification. Moreover, we propose an optimized Raman scanning strategy to minimize the acquisition time while simultaneously identifying the ...

Carbon nanotubes focus the attention of many scientists because of their huge potential of industrial applications, but there is a paucity of information on the toxicological properties of this material. The aim of this experimental study was to characterize the biological reactivity of purified multi-wall carbon nanotubes in the rat lung and in vitro. Multi-wall carbon nanotubes (CNT) or ground CNT were administered intratracheally (0.5, 2 or 5 mg) to Sprague–Dawley rats and we estimated lung persistence, inflammation and fibrosis biochemically and histologically. CNT and ground CNT were still present in the lung after 60 days (80% and 40% of the lowest dose) and both induced inflammatory and fibrotic reactions. At 2 months, pulmonary lesions induced by CNT were characterized by the formation of collagen-rich granulomas protruding in the bronchial lumen, in association with alveolitis in the surrounding tissues. These lesions were caused by the accumulation of large CNT agglomerates in the airways. Ground CNT were better dispersed in the lung parenchyma and also induced inflammatory and fibrotic responses. Both CNT and ground CNT stimulated the production of TNF-α in the lung of treated animals. In vitro, ground CNT induced the overproduction of TNF-α by macrophages. These results suggest that carbon nanotubes are potentially toxic to humans and that strict industrial hygiene measures should to be taken to limit exposure during their manipulation.